One of the really big issues with the evolution to larger sensors is as Don and others have mentioned ... the optics. For EAA/live viewing we are generally used to working at ratios like f3 to f5. Larger sensors start to put us in the same league optics expensive wise as the imaging folks who traditionally use reducers in the .8x range on more expensive scopes ... only we have an even more extreme problem.
Going down to the f5 and lower ranges with larger sensors is going to require field flatteners as well as reducers with enough aperture to keep vignetting at bay. That means a lot more money for the optics.
We either start with faster optics (f4 Newtonians) and add field flatteners (proven and generally reasonable price wise), or the extra complexity and expense of larger aperture and better corrected reducers on slower scopes (f7 refractors or f8 RCs for example).
It's going to become increasingly tough using our beloved native f10 SCTs with bigger sensors at the f ratios we've become accustomed to.